1. Technical Field
The invention relates generally to pusher furnaces. More particularly, the invention relates to a pusher furnace in which pusher plates are moved therethrough in a continuous manner. Specifically, the invention relates to loading and unloading mechanisms for providing such continuous movement of the pusher plates.
2. Background Information
Pusher furnaces are generally known in which a load to be heated is seated on a pusher plate which slides on rails extending through a heating chamber. However, many of these are indexing furnaces in which the pusher plate and load move in intermittent steps through the furnace. In addition, many pusher furnaces are relatively short. Yet there are certain types of products which require that a pusher furnace be both continuous and relatively long and include a heating section followed by a cooling section. Some of these products must also be fired at very high temperatures. For example, silicone carbide products fall in this category and more particularly diesel particulate filters. Production of products such as these require heating of the load in a series of heating zones having different temperature ranges which are closely controlled. Thus, there is a need in the art for an extremely long pusher furnace which is capable of firing to very high temperatures and which moves the loads therethrough in a continuous manner. As a result, there is a need for continuous loading and unloading mechanisms which can ensure that the loads are moved through the furnace in a continuous manner, as opposed to an indexing furnace wherein as the load briefly stops, it continues to absorb heat which may result in surface or interior temperatures which are higher than allowable to achieve a successful product.